A co-inventor of the present invention is also a co-inventor to "Novel Packaging Compositions That Extend The Shelf Life Of Oil-Containing Foods", U.S. Ser. No. 07/724,421, filed Jul. 3, 1991, in which PEI is disclosed to have aldehyde scavenging capabilities (which can extend shelf life of oil-containing foods) when used as part of a packaging material. The present invention is an important improvement to U.S. Ser. No. 724,421.
U.S. Ser. No. 724,421 teaches the application of a thin coating of PEI as part of a multilayer composite film. However, the application of a thin coating of a material adds to the overall manufacturing complexity and creates an additional layer to be accomodated in a multilayer packaging structure.
PEI is a highly viscous liquid and is generally considered not to be pumpable. Furthermore, liquids generally do not pre-compound well with polymeric materials which are solid at room temperature, because the liquid will generally tend to bloom to the surface or otherwise migrate within the solid polymeric material; surface migration of PEI would generally cause the pre-compounded granules to stick to one another and inhibit flow into an extruder or the like.
The present invention overcomes or dramatically decreases the above described problems.